66536640 has 280 divisors, whose sum is σ = 252264672. Its totient is φ = 16588800.

The previous prime is 66536621. The next prime is 66536647. The reversal of 66536640 is 4663566.

66536640 is a `hidden beast` number, since 6 + 6 + 5 + 3 + 6 + 640 = 666.

66536640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 66536595 and 66536604.

It is not an unprimeable number, because it can be changed into a prime (66536647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 440565 + ... + 440715.

Almost surely, 2^66536640 is an apocalyptic number.

66536640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66536640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (126132336).

66536640 is an abundant number, since it is smaller than the sum of its proper divisors (185728032).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66536640 is a wasteful number, since it uses less digits than its factorization.

66536640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197 (or 178 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 66536640 is about 8156.9994483266. Note that the first 3 decimals coincide. The cubic root of 66536640 is about 405.2163453161.

It can be divided in two parts, 66536 and 640, that added together give a palindrome (67176).

The spelling of 66536640 in words is "sixty-six million, five hundred thirty-six thousand, six hundred forty".